Cisco IPSec Malformed IKE Packet Vulnerability

Summary

A malformed Internet Key Exchange (IKE) packet may cause the Cisco
Catalyst 6500 Series Switch or the Cisco 7600 Series Internet Router to reload.
Only devices running Cisco IOS software with Crypto support are
affected.

This vulnerability is documented as Cisco bug ID CSCed30113. There are
workarounds available to mitigate the effects of this vulnerability.

Cisco has made free software available to address this vulnerability
for all affected customers.

The title of this advisory has been updated from "Cisco IPSec VPN
Services Module Malformed IKE Packet Vulnerability" to the current title due to
a change in the products affected no longer being limited to those devices with
a VPN Services Module installed.

All Cisco Catalyst 6500 Series Switch and the Cisco 7600 Series
Internet Router hardware running the following Cisco IOS releases are affected
by this vulnerability.

Release Train

Affected Releases

12.2SXA

earlier than 12.2(17b)SXA

12.2SXB

earlier than 12.2(17d)SXB

12.2SX

12.2(17a)SX through 12.2(17a)SX4

12.2SY

earlier than 12.2(14)SY3

Products Confirmed Not Vulnerable

Cisco Catalyst 6500 Series Switches and Cisco 7600 Series Internet
Routers running Cisco IOS release train 12.1E are not affected by this
vulnerability.

To determine your software revision, type show
version at the command line prompt.

No other Cisco products are currently known to be affected by this
vulnerability.

Details

A malformed IKE packet may cause an affected device to reload.

This vulnerability could be used to conduct a Denial of Service (DoS)
attack against a vulnerable device. This vulnerability is known to only exist
in the modified IKE code which was incorporated in the 12.2SXA, 12.2SXB, 12.2SX
and 12.2SY Cisco IOS software release trains.

Workarounds

The effectiveness of any workaround is dependent on specific customer
situations such as product mix, network topology, traffic behavior, and
organizational mission. Due to the variety of affected products and releases,
customers should consult with their service provider or support organization to
ensure any applied workaround is the most appropriate for use in the intended
network before it is deployed.

Customers that do not require IPSec functionality on their devices can
use the command 'no crypto isakmp enable' in configuration mode to disable
processing of IPSec and eliminate their exposure.

As a possible mitigation, access-lists could be applied on the affected
IOS platforms to limit the source IP addresses permitted to establish IPSec
sessions to the device.

Fixed Software

This vulnerability has been fixed in the following Cisco IOS releases
for the Cisco Catalyst 6500 Series Switch and the Cisco 7600 Series Internet
Router hardware:

In all cases, customers should exercise caution to be certain the
devices to be upgraded contain sufficient memory and that current hardware and
software configurations will continue to be supported properly by the new
release. If the information is not clear, contact the Cisco Technical
Assistance Center ("TAC") for assistance.

Exploitation and Public Announcements

The Cisco PSIRT is not aware of any public announcements or malicious
use of the vulnerability described in this advisory.

This vulnerability was reported to Cisco PSIRT by a customer.

Cisco Security Vulnerability Policy

To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy. This document also contains instructions for obtaining fixed software and receiving security vulnerability information from Cisco.

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Cisco Security Vulnerability Policy

To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy. This document also contains instructions for obtaining fixed software and receiving security vulnerability information from Cisco.